As far as flight delays go, this was a tough one to gripe about. Early Thursday morning, Southwest Airlines Flight 3606 turned around in midair, halting its trip to Dallas to return to Seattle. Among the plane’s cargo was a human heart—whoever had ordered it sent from Sacramento didn’t realize they were missing a cooler covered in biohazard stickers until the plane had left Sea-Tac airport and was a third of the way to Texas. And so the pilots booked it back to the Emerald City. But here’s where the story gets weird: According to the The Seattle Times, no hospitals in the region were awaiting the wayward organ.

Who was the owner of this lonely heart? How did it wind up flying commercial and suffering the fate of so many a lost bag? Transplant organs are precious commodities that require surgically precise logistics to get from bodies that deed to bodies in need. The flight from Sacramento to Seattle alone would have been pushing the time limit before the heart was no good, and that’s not counting travel to and from the airport, boarding, taxiing, and the potential for delays. It’s almost like whoever shipped it to Seattle had never intended for this heart to beat again.

Bingo. “There was no intended recipient,” says Deanna Santana, public relations manager for Sierra Donor Services, the organ procurement organization that sent this heart from Sacramento to Seattle. “We were not functioning as an organ procurement, we were functioning as a tissue recovery for heart valves, which were to be sent to a tissue processor,” she says. This might sound like a superficial distinction, but when it comes to transplants, it’s the difference between life or death.

Owner of a Donor Heart

If you recall middle-school biology, tissues are collections of identical cells all doing the same job. Organs are collections of tissues working in concert for some sort of more complex function: Hearts pump blood, lungs add oxygen to blood, kidneys remove toxins from blood, and there are a bunch of others performing various blood- and non-blood-related jobs. Because organs are so complex, they have to be recovered from a living body. But, for obvious ethical (not to mention legal) reasons, that living body must be brain-dead.

“The organ procurement process starts when somebody in a hospital has a body that’s bleeding out, but their brain is already gone,” says Scott Perry, an independent transplant coordinator based in Pittsburgh. Under federal law, any hospital that receives funding from the Center for Medicare and Medicaid Services (which is most hospitals) has to contact their local Organ Procurement Organization whenever a patient meets these conditions. (Sierra Donor Services is one of the 58 nationwide organ procurement organizations.) This sets the organ donor process into motion.

The first thing these organizations do upon contact is check whether the patient has any medical conditions, such as cancer, that might disqualify them as a donor. If it’s all clear, the organ procurement organization contacts the family to get consent (or, if the deceased had signed an organ donor form, inform the family of their choice). Once that’s settled, the organ procurement organization sets about finding a suitable recipient. They do this by plugging the organ’s information into a computer system called DonorNet, which contains details on every person needing an organ in the US. DonorNet’s algorithm ranks potential recipients on a number of factors, like geography, blood type, medical urgency, and organ size—a preteen’s lungs won’t work in an adult’s chest, for instance. One important note: DonorNet generates a unique list for every organ, and its parameters are always changing to make organ distribution more fair, equitable, and inclusive.

The computer program only determines the match at a superficial level. Transplant coordinators like Perry talk to the doctors and figure out whether that specific organ is a good fit for this recipient’s need. The transplant coordinator gets the organ from one body to the next. Once the transplant coordinator settles on a match, they dispatch a surgeon—typically from the organ recipient’s hospital—to go recover the organ.

Now the clock is really ticking. Every recovered organ has an expiration date. This time fluctuates based on the age of the donor, the condition of the organ, and even the organ’s type. For instance, a kidney from a 30-year-old donor can take up to 30 hours of cold time. Hearts are a lot less stable. “Doctors are leery over any heart that goes farther than two hours away,” Perry says.

That last detail didn’t escape passengers on the Dallas-bound flight—the turnaround added three hours to the time it had already spent traveling from Sacramento to Seattle. People told The Seattle Times they were Googling transfer times, and their worries that the heart wouldn’t last superseded any annoyance at the delay. Andrew Gottschalk, a passenger on the flight, told the Times that every person on board was “happy to save a life.”

Maybe they should have been a little annoyed. Remember all the intricate checks and balances that go into being an organ donor—dead brain, living body, ticking clock? This heart hadn’t met those qualifications when it was recovered back in Sacramento. So, it was instead recovered for the tissue in its valves. “Anybody can be a tissue donor, all you have to be is dead,” Perry says. Tissues don’t have to go from body to body. This one was bound for a tissue bank called LifeNet Health in Renton, a Seattle suburb. Apparently, the courier simply forgot to pick it up. Which explains why no Seattle hospitals were worrying over their misplaced muscle.

Tissue also lasts a lot longer on ice than organs. Santana says this valve tissue had 48 hours to make it from Sacramento to the tissue-processing facility. “This delay did not affect that,” she says. Even with the delay, the tissue arrived in Seattle with 12 hours to spare. “Despite the detour, all is well,” Santana says. Well, maybe not all. The Southwest flight suffered another delay—this one mechanical—after arriving back in Seattle. It finally reached Dallas more than eight hours after its scheduled arrival.

When the Timesfollowed up with Gottschalk to inform him of the tissue’s fate, he was less magnanimous: “As it turns out, there was nothing critical about the shipment,” Gottschalk told the paper. “The shipment may as well have been a suitcase.”

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